The present invention relates generally to inkjet printers, and more particularly to a carriage guide for a carriage of an inkjet printer.
A conventional inkjet printing system includes a printhead assembly, an ink supply which supplies liquid ink to the printhead assembly, and an electronic controller which controls the printhead assembly. The printhead assembly, commonly referred to as a print cartridge or pen, ejects ink drops through a plurality of orifices or nozzles and toward a print medium, such as a sheet of paper, so as to print onto the print medium. Typically, the orifices are arranged in one or more arrays such that properly sequenced ejection of ink from the orifices causes characters or other images to be printed upon the print medium as the printhead assembly and the print medium are moved relative to each other. To position the printhead assembly relative to the print medium, the conventional inkjet printing system includes a carriage assembly. As such, the printhead assembly is positioned in, and supported by, the carriage assembly. As illustrated in FIG. 1, a conventional carriage assembly 200 typically includes a carriage 202 and a carriage guide 204. As such, the carriage supports a print cartridge 206, including a printhead assembly 207, for movement relative to a print medium 208. Typically, the carriage guide includes a carriage rod 210 supported by sidewalls and mounted horizontally to guide and retain the carriage. To stabilize the carriage and prevent rotation of the carriage about the carriage rod, the carriage assembly typically includes an anti-rotation rail 212 supported by a hanger 214. In addition, adjustment of the anti-rotation rail on the hanger varies the spacing between the printhead assembly and the print medium. Thus, to establish the desired spacing between the printhead assembly and the print medium, the anti-rotation rail is adjusted and secured in position during assembly. Other designs have used two spaced carriage rods to guide and stabilize carriage.
Typically, the carriage rod is a precision ground steel rod. As such, the precision ground steel rod allows the carriage to move with minimal impediment with frequent changes in direction along the carriage guide. Thus, in order to maintain a precise and consistent spacing between the printhead assembly and the print medium, the precision ground steel rod is fabricated to very close tolerances. In addition, the precision ground steel rod requires assembly which, understandably, is labor intensive. Thus, the cost required to fabricate and assemble the precision ground steel rod results in a more expensive manufacturing process.
Accordingly, a need exists for a carriage guide of reduced cost which supports a carriage of an inkjet printer for movement with minimal impediment with frequent changes in direction along the carriage guide.
One aspect of the present invention provides a carriage guide for a carriage of an inkjet printer. The carriage guide includes a carriage track having a longitudinal axis, an anti-rotation rail spaced from the carriage track and oriented substantially parallel with the longitudinal axis of the carriage track, and a bridge joined to the carriage track and the anti-rotation rail. The carriage track and the anti-rotation rail each form at least one support surface configured to slidably support the carriage for movement along the longitudinal axis of th carriage track.
Another aspect of the present invention provides an inkjet printer. The inkjet printer includes a carriage track having a longitudinal axis, an anti-rotation rail spaced from the carriage track and oriented substantially parallel with the longitudinal axis of the carriage track, a bridge extending between the carriage track and the anti-rotation rail, and a carriage slidably supported by the carriage track and the anti-rotation rail for movement along the longitudinal axis of the carriage track. The carriage track and the anti-rotation rail each from at least one support surface and the carriage has at least two contact surfaces. The at least two contact surfaces of the carriage contact the at least one support surface of the carriage track and the at least one support surface of the anti-rotation rail.
Another aspect of the present invention provides a method of supporting a carriage of an inkjet printer. The method includes extending a carriage track along a longitudinal axis to form at least one first support surface for the carriage, spacing an anti-rotation rail from the carriage track and orienting the anti-rotation rail substantially parallel with the longitudinal axis to form at least one second support surface for the carriage, and extending a bridge between the carriage track and the anti-rotation rail.